1. Field of the Invention
The present invention relates to a process for the production of a phosphate-based aromatic phosphorus-containing polymer. More specifically, it relates to a novel process for the production of a phosphate-based aromatic phosphorus-containing polymer, in which phosphorus pentachloride is used as a component for a phosphorus material.
2. Prior Art of the Invention
Phosphorus-containing organic compounds are attracting attention as highly functional materials for high molecular weight compounds (resins). Above all, a phosphate-based aromatic phosphorus-containing polymer is useful as a flame retardant, a stabilizer, a plasticizer, a compatibilizer and a lubricant for high molecular weight compounds (resins).
A phosphate-based aromatic phosphorus-containing polymer has been hitherto produced by a method in which phosphorus oxychloride, dihydric phenol and monohydric phenol are allowed to react in the presence of a proper catalyst (Lewis acid) such as aluminum chloride or a hydrogenchloride scavenger such as an amine. However, the above method involves a problem in that it takes time to remove and dispose of the used catalyst. There is also known a method which dichlorophenyl phosphate and dihydric phenol are allowed to react in the absence of a catalyst (Polymer, 757, Apr. 29, 1988), while this method has a defect in that the reaction takes a long period of time. Further, a phosphate-based phosphorus-containing polymer can be produced by an ester interchange reaction of a combination of dihydric phenol and triphenyl phosphate (Japanese Patent Publication No. 40735/1991). while the defect with this production is that the required reaction conditions are so severe that the reactor and the procedures for the reaction are complicated.